This invention relates generally to gas turbine engines, and more specifically to turbine blades used in gas turbine engines.
In at least some gas turbine engines, turbine blades used within the engine are cast to an approximate final shape. Portions of the turbine blades, including, but not limited to, a root portion, are then shaped to a final desired form by a shaping technique, such as grinding. The finished turbine blades are assembled into a turbine disk or rotor, such that a “dovetail” formed on each turbine blade engages a complimentarily shaped slot on the turbine disk.
Generally, turbine blades are constructed from a high-temperature, high-strength alloy that is adapted to withstand the temperatures and stresses imposed on the parts of a turbine assembly. Because of the high cost of materials, casting operations, and finishing operations, some turbine blades, after being in service, are refurbished to restore the original aerodynamic contours of portions of the blades. At least some known turbine blade repairs require building up the surface being repaired with a weld bead, and then grinding the surface back to its original contour.
Occasionally, while refurbishing a turbine blade, because the dovetail section has been housed in the rotor disk slot and out of the gas stream. It may be the only datum available for referencing for the grinding operation. However, because the dovetail serrations may be small, in many applications, the clamping mechanisms may inhibit operation of the grinding machines. In contrast, other clamping arrangements use long locating pins to clamp the component such that grinding equipment operations are not inhibited. However, because such fixtures must generally be very large to generate a sufficient clamping force, such fixtures are generally much more expensive and far less portable than other clamping mechanisms.